#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef double db;

#define in read()
#define pii pair<int,int>
#define fi first
#define se second
#define FILE(x) freopen(x".in","r",stdin);\
	freopen(x".out","w",stdout);
#define pb push_back

int read(){
	int x = 0,sgn = 1;char ch = getchar();
	for(;!isdigit(ch);ch = getchar()) if(ch == '-') sgn = -1;
	for(;isdigit(ch);ch = getchar()) x = (x<<1)+(x<<3)+(ch^48);
	return x*sgn;
}

int k;
ll ans;

int main (){
#ifndef ONLINE_JUDGE
	freopen("1.in","r",stdin);
#endif
	k = in;
	for(int i = 1;i <= k;i++){
		int x = k / i;
		for(int l = 1,r;l <= x;l = r+1){
			r = min(x,x/(x/l));
			ans += 1ll * (r - l + 1) * (x / l);
		}
	}
	printf("%lld\n",ans);
	return 0;
}

